A light emitting diode (LED) is a semiconductor light emitting device that converts current into light.
Wavelengths of light emitted by the LED may vary according to semiconductor materials. This is because the emitted wavelengths of light are determined by band-gaps of semiconductor materials, which represent energy difference between electrons of a valence band and electrons of a conduction band.
Recently, research for improving the brightness of LEDs has been actively conducted. As a result, LEDs are now used as various kinds of light sources for displays, cars and general lighting. Furthermore, LEDs that efficiently emit excellent white color light by using fluorescent materials or combining LEDs of various colors may be realized.